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From "Ivan V." <iveselovs...@gridgain.com>
Subject Re: Igfs PURGE events: do we need them?
Date Mon, 23 Nov 2015 11:45:13 GMT
Hi, Dmitriy,
this is not difficult to support the events properly, we just need to store
last path of each file or make sure it is guaranteed to be calculatable
when the file is already in TRASH (this is needed because each PURGE event
must contain the path of the file that is purged).

On Fri, Nov 20, 2015 at 10:45 PM, Dmitriy Setrakyan <dsetrakyan@apache.org>
wrote:

> On Fri, Nov 20, 2015 at 11:08 AM, Ivan V. <iveselovskiy@gridgain.com>
> wrote:
>
> > Hi, Dmitriy,
> > to wait for memory freeing we have
> > method
> > org.apache.ignite.internal.processors.igfs.IgfsEx#awaitDeletesAsync()
> > which returns a Future that can be awaited (with a timeout or without).
> > Also during recent fix https://issues.apache.org/jira/browse/IGNITE-1510
> > we
> > introduced new method IgfsEx#clear(IgfsPath) that deletes the specified
> > path and waits for the garbage data cleanup.
> > These methods have more or less convenient usage pattern.
> > But it is much more difficult to use PURGE events in practice. E.g. how
> to
> > know how many events to expect, and how to track what events have
> arrived,
> > and what have not?
> >
>
> Ivan, I see your point. There are 2 ways to resolve it, we either deprecate
> the event, or we support it properly. How difficult, in your opinion, it
> would be to support this even properly.
>
>
> >
> > On Fri, Nov 20, 2015 at 9:10 PM, Dmitriy Setrakyan <
> dsetrakyan@apache.org>
> > wrote:
> >
> > > Ivan,
> > >
> > > The importance of the PURGE event has to do with notification about
> > freeing
> > > memory, otherwise occupied by a deleted file.
> > >
> > > How hard do you think would be making the PURGE behavior consistent
> > between
> > > directory and file deletions?
> > >
> > > D
> > >
> > > On Fri, Nov 20, 2015 at 8:15 AM, Ivan V. <iveselovskiy@gridgain.com>
> > > wrote:
> > >
> > > > Hi, dev,
> > > > need opinions on the question discussed in
> > > > https://issues.apache.org/jira/browse/IGNITE-1679  (IGFS: Purge
> event
> > is
> > > > inconsistent).
> > > > In short: in Igfs we have "soft" delete that moves the deleted file
> or
> > > > folder to special "TRASH" folder.
> > > > Special async worker walks inside TRASH and removes the items
> > > permanently.
> > > > When an item is completely removed, an event of type
> > > > org.apache.ignite.events.EventType#EVT_IGFS_FILE_PURGED  is fired.
> > > > But such events are now fired only for files, and only in case if
> such
> > > file
> > > > was deleted itself, but not a part of a folder sub-tree. It's quite
> > > obvious
> > > > that such behavior is not quite consistent, so we should either get
> rid
> > > of
> > > > PURGE events at all, or make them consistent.
> > > > In the latter case it would be good to have answer to the question:
> > what
> > > > are real  use cases when we may need the purge events ? (Now they
> seem
> > to
> > > > be used in tests only).
> > > > If we don't have such real use cases, are there any objections to get
> > rid
> > > > of the purge events at all?
> > > > Thanks in advance.
> > > >
> > >
> >
>

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